合肥市TSP和PM2.5中7Be和210Pb浓度及变化研究

目的 研究合肥市TSP和PM_2.5颗粒物中天然放射性核素⁷Be和²¹⁰Pb浓度的年度变化情况及其与颗粒物质量的关系。方法 通过大流量气溶胶采样器和PM_2.5粒径切割器采集合肥市一年中各月份同时段的TSP和PM_2.5样品，使用超低本底高纯锗谱仪对样品中放射性核素⁷Be和²¹⁰Pb的活度进行测量。结果 研究结果表明：TSP样品中⁷Be和²¹⁰Pb的活度浓度年均值分别为（5.34 ±1.48） mBq/m³和（1.66 ±0.84） mBq/m³，PM_2.5样品中⁷Be和²¹⁰Pb的活度浓度年均值分别为（4.32 ±1.23） mBq/m³和（1.35 ±0.68） mBq/m³；PM_2.5与TSP中⁷Be的活度浓度月均值比值范围为0.59～0.99，PM_2.5与TSP中²¹⁰Pb的活度浓度月均值比值范围为0.61～0.94；TSP和PM_2.5中⁷Be和²¹⁰Pb的活度浓度的年度变化趋势均与颗粒物质量的年度变化趋势基本一致，呈现冬春季节高，而夏秋季节相对较低，但是TSP和PM_2.5中⁷Be和²¹⁰Pb的比活度均与颗粒物质量均无明显的相关性。结论 合肥市TSP和PM_2.5颗粒物中⁷Be和²¹⁰Pb的活度浓度主要取决于颗粒物质量，并且大气颗粒物中⁷Be和²¹⁰Pb主要分布于PM_2.5中，因此，在评估大气中放射性颗粒物对人体造成的危害时应主要考虑PM_2.5中的放射性核素的贡献。

Study on concentrations and changes of 7Be and 210Pb in TSP and PM2.5 in Hefei

Objective This study focuses on the annual variation of the concentration of radionuclides ⁷Be and ²¹⁰Pb in TSP and PM_2.5 in Hefei and relationship between activity concentration and mass concentration of particle matter. Methods TSP and PM_2.5 samples of the same period of each month in Hefei were collected by large-flow aerosol sampler and PM_2.5 particle size cutter, respectively. The activity concentrations of ⁷Be and ²¹⁰Pb in samples were measured by the ultra-low background HPGe spectrometer. Results The results showed that the annual averaged values of the activity concentrations of ⁷Be and ²¹⁰Pb in TSP samples were (5.34 ±1.48) mBq/m³ and (1.66 ±0.84) mBq/m³, respectively. The annual averaged values of the activity concentrations of ⁷Be and ²¹⁰Pb in PM_2.5 samples were (4.32 ±1.23) mBq/m³ and (1.35 ±0.68) mBq/m³, respectively. The ratio of the monthly averaged value of the activity concentrations of ⁷Be and ²¹⁰Pb in PM_2.5 and TSP ranged from 0.59 to 0.99, and 0.61 to 0.94, respectively; The annual variation trends of ⁷Be and ²¹⁰Pb activity concentrations in TSP and PM_2.5 were basically consistent with the annual variation trend of mass concentration of particulate matter, showing high in winter and spring seasons and relatively low in summer and autumn seasons. However, the specific activities of ⁷Be and ²¹⁰Pb in TSP and PM_2.5 had no significant correlation with the mass concentration of particulate matter. Conclusion The activity concentrations of ⁷Be and ²¹⁰Pb in the TSP and PM_2.5 in Hefei mainly depend on mass concentration of particle matter, and the ⁷Be and ²¹⁰Pb in the atmospheric particulate matter are mainly distributed in PM_2.5. Therefore, further study should mainly consider the contribution of radioactive particles in PM_2.5 when assessing the hazards of radioactive particulate matter in the atmosphere to humans.